SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c03108ed49cbe1e6f2e5c7e978279af88f91cbf8aff27d2d028adab146fbba7' 
  AND token = 'v2t6YusvlrKhOS1VqYnUxLjwYmX8QLetX9nip+HhGGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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