SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6944a4444a715442412703deeabf8805b70b65c67a8a5fd403ebca933767b93b' 
  AND token = 'DVTiENzQ+YiuvzFtnmg4nhSDcQU/opkcZKnEtPd+fZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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