Custom template redirect based on url vars

I am using a custom URL on my menu to show the most viewed posts by passing the variables to the url as

https://website.com/?v_sortby=views&v_orderby=desc

However I want to use a custom template to display the results.

I tried the following but it doest work. I am having trouble finding a fix, can anyone help.

function custom_template($template) {
  global $wp;
  if ($wp->query_vars['template']=='basic') {
    return dirname( __FILE__ ) . '/basic.php';
  }
  else {
    return $template;
  }
}
add_filter('template_redirect', 'custom_template');