SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6aa3d781509259560ab5b8a4ed5f6710a61d2f0a3ccd903b16d7ff1130f76fb' 
  AND token = 'MQMvRzsz92qZW/z+iiSD9fZ+sh08CMnwdIBP1cpl7UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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