SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '318a1b0ee6e23a7cf9810977c3e7c1bf703a9d83a8f9c31aca7383161140803f' 
  AND token = 'jK6zfduvv1oyrEki1FIeiBSCRgGO5PYn+YBVzyQ5Jac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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