SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6457f89b64656601656eb45412e8bf51d432452de34318a4be5b1703d740a628' 
  AND token = 'ojh9WNMDeIewwacYD8KgCQCEqqYsVzJWfCxj4mnH6TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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