function jas_gecko_os_locate_template( $located, $template_name, $args, $template_path, $default_path ) {
    if ( $template_name == 'single-product/add-to-cart/variable.php' ) {
        global $post;

        $tmp = get_post_meta( $post->ID, '_allow_openswatch', true );
        if ( $tmp != 0 ) {
            // Change the path to new template file here
            return get_stylesheet_directory_uri() . 'your_file_here.php';
        }
    }
    return $located;
}
add_filter( 'wc_get_template','jas_gecko_os_locate_template', 20, 5 );