SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65912e409852aef6593f453fde3dfd13431b44a09f54d9c63a4784c464800807' 
  AND token = 'NO5O1HTSFMQzYWZXAxEoronVrILvccdPVnvAQD8C3A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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