Laravel: Set incoming request's GET param

I want to append a new GET param to incoming request. How do I do this?

This is what I have tried and is not working,

Route::group(['prefix' => 'api'], function () {
  $_GET['key'] = getKeyForSession();
  Route::get('teams', 'TeamController@index');
});

Do I need to write a middleware for this? Even if I do, how do I set the GET param key?

via Chebli Mohamed