Query post order by post and desc not working

post is not a valid value for orderby parameter neither DESC. You can choose any of these values. Also, you should stop using query_post.

<?php
$args = array( 
            'post_type'      => 'ranking',
            'orderby'        => 'menu_order', 
            'order'          => 'DESC',                                    
            'posts_per_page' => 10,
            'meta_key'       => 'top10',
            'meta_value'     => 'sim'
);
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) {
     $loop->the_post();
     //Do whatever you want with the posts
}
//After the loop reset post data
wp_reset_postdata();
?>