SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db5c3c6817f7ca5e2d84a1cb34bb77481e4d88aaa079e6e1a6bb1b5bf1c3b473' 
  AND token = 'mhCDw++163H5zTXpGR6WABwkh3nZ7GA0TlIibX/mAaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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