Woocommerce wp-admin search products through custom meta value too

It depends. There are plugins that can add this functionality, I have used SearchWP in the past, it works well with WooCommerce.

You could also write your own custom function and add it to your theme’s functions.php file. Something like this should work.

function my_custom_search( $query ) {
    if( ! is_admin() && $query->is_main_query() ) {
        if ( $query->is_search() ) { 

            $meta_query = array(
                'key'       => 'custom_meta',
                'value'     => $query->query['s'],
                'compare'   => 'LIKE'  
            );

            $query->set('meta_query', $meta_query);

        }
    }
}

add_action('pre_get_posts' , 'my_custom_search');