SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66cd6ec14ad6fd5f701e3f72b26db824b9d1bb6c800145ef4237103dd17d6755' 
  AND token = 'VBKrRP2Zu1NlEvdduX8dkQ0lav5tgmYUneqvBK9M3Lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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