You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'ORDER BY orden ASC' at line 3
SELECT ap.* , ap_lang.nombre, ap_lang.keywords, ap_lang.info_add_1, ap_lang.info_add_2, ap_lang.descripcion, ap_lang.especificaciones FROM productos AS ap LEFT JOIN productos_idiomas AS ap_lang ON ap.id = ap_lang.id WHERE ap_lang.idioma= "es" AND id_padre = ORDER BY orden ASC