Ayuda optimizar consulta

[Xpiral]

Buenas he tenido problemas con el hosting porque me dicen que hay sobre carga de las consultas, estoy utilizando la base de datos de wordpress y la acomode a mi gusto con consultas mias, pero aun asi esta consumiendo mucho alguna ayuda porfavor, =).



$peliculas=mysql_query("SELECT t1.post_id AS post_id, t1.meta_key AS meta_key, t1.meta_value AS meta_value, t2.ID AS ID, t2.post_type AS post_type, t2.post_title AS post_title, t2.post_date AS post_date, t2.post_name AS post_name FROM wp_postmeta AS t1 INNER JOIN wp_posts AS t2 ON (t1.meta_key = 'thumbnail' && t2.post_type = 'post' && t1.post_id = t2.ID) ORDER BY t2.post_date DESC limit 0,21",$conexion);