SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f95d3655760c4ddc20d46fc78781afe24e0aec92716401a7d99e12eb3582b294' 
  AND token = '7B7Nos/iAZcxnFls+6U3q3tAQg2uzAtKBZQhhUkvi38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}