SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb67966d22979517bdebfa05bec142ff0cfe4414cb1fd34e02998983ddd8e5b' 
  AND token = 'xfcuhMyrkFWRwiAJXplGTGIvuxZboDTHE9e4qSXaVwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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