SELECT 
  cscart_product_filters.filter_id, 
  cscart_product_features_values.variant_id 
FROM 
  cscart_product_features_values 
  LEFT JOIN cscart_products as products ON products.product_id = cscart_product_features_values.product_id 
  LEFT JOIN cscart_product_filters ON cscart_product_filters.feature_id = cscart_product_features_values.feature_id 
  LEFT JOIN cscart_product_features ON cscart_product_features.feature_id = cscart_product_features_values.feature_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
WHERE 
  cscart_product_filters.filter_id IN (3) 
  AND cscart_product_features_values.feature_id IN (13) 
  AND cscart_product_features_values.lang_code = 'ru' 
  AND cscart_categories.category_id IN (4) 
  AND cscart_categories.company_id = 1 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND cscart_product_features.feature_type IN ('S', 'M', 'E') 
GROUP BY 
  cscart_product_features_values.variant_id

Query time 0.00168

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.14"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "0.71"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_product_filters",
            "access_type": "const",
            "possible_keys": [
              "PRIMARY",
              "feature_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "filter_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 1,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.00",
              "eval_cost": "0.20",
              "prefix_cost": "0.00",
              "data_read_per_join": "64"
            },
            "used_columns": [
              "filter_id",
              "feature_id"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_product_features",
            "access_type": "const",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "feature_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 1,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.00",
              "eval_cost": "0.20",
              "prefix_cost": "0.00",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "feature_id",
              "feature_type"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "const",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 1,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.00",
              "eval_cost": "0.20",
              "prefix_cost": "0.00",
              "data_read_per_join": "4K"
            },
            "used_columns": [
              "category_id",
              "company_id",
              "usergroup_ids",
              "status"
            ]
          }
        },
        {
          "table": {
            "table_name": "products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 1,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "1.00",
              "eval_cost": "0.20",
              "prefix_cost": "1.20",
              "data_read_per_join": "16"
            },
            "used_columns": [
              "product_id",
              "category_id"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_product_features_values",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "fl",
              "variant_id",
              "lang_code",
              "product_id",
              "fpl"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "feature_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "db_emaika1.products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "85.71",
            "using_index": true,
            "cost_info": {
              "read_cost": "1.00",
              "eval_cost": "0.17",
              "prefix_cost": "2.40",
              "data_read_per_join": "678"
            },
            "used_columns": [
              "feature_id",
              "product_id",
              "variant_id",
              "lang_code"
            ],
            "attached_condition": "(`db_emaika1`.`cscart_product_features_values`.`lang_code` = 'ru')"
          }
        },
        {
          "table": {
            "table_name": "products",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "status"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "ref": [
              "db_emaika1.products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "83.33",
            "cost_info": {
              "read_cost": "0.86",
              "eval_cost": "0.14",
              "prefix_cost": "3.43",
              "data_read_per_join": "5K"
            },
            "used_columns": [
              "product_id",
              "status",
              "usergroup_ids"
            ],
            "attached_condition": "(((`db_emaika1`.`products`.`usergroup_ids` = '') or find_in_set(0,`db_emaika1`.`products`.`usergroup_ids`) or find_in_set(1,`db_emaika1`.`products`.`usergroup_ids`)) and (`db_emaika1`.`products`.`status` = 'A'))"
          }
        }
      ]
    }
  }
}