SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e1be6bdc4d63f19f2ba8f09ae043dd84873b1e85136b101d4285aac902bfd47' 
  AND token = 'l586H0WLxctSeZ1dIydTDAUpvkCm1J9aB8zDBZH3DhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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