SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '480d79af985b56a22ab8badd688f7a81b94b342c240f98799824d347de008650' 
  AND token = 'EJsW6AufbRGVgTYm5byJ4n18/afBOOM86+wqTgKZAmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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