SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419732b5c2f96d675af318890ccf9291fd203c152fa90657c52b948296d75c6f' 
  AND token = '9J1W9XR/4wiunXjBYRvDlOh6+U68ne50X5uh4EZGnk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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