Move Post to different category if post_meta field is 0 or is 2 days old?

Is it possible to move a post to an another category if post_meta field is 0 ?
I’m building a reverse order vote, every post have by default 10 votes and after a user vote, removes one vote by updating the post_meta, now i try to move the post to an another category if the votes field is 0 or 2 days old.

I have found a solution here that moves a post to an another category if is a past date from this in the database.
It runs every hour to do the check

if (!wp_next_scheduled('sfn_expire_hook')){
    wp_schedule_event( time(), 'hourly', 'sfn_expire_hook');
}

add_action( 'sfn_expire_hook', 'sfn_show_expire');
function sfn_show_expire(){
    global $wpdb;
    $server_time = date('mdy');
    $result = $wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_type = 'post' AND post_status = 'publish'");
    if( !empty($result)) foreach ($result as $a){
        $show_time = get_the_time('mdy', $a->ID);
        if ( $server_time > $show_time ){
           $my_post = array();
           $my_post['ID'] = $a->ID;
           $my_post['post_status'] = 'draft';
           wp_update_post( $my_post );
        }
    } // end foreach
}

can someone help me to extend this to check for 2 days old posts and if post_meta “votes” is “0” also?

thanks a lot,
Philip