When condition on eloquent with the column values on the table

How can I add in conditional the value of the query i'm using on when function of eloquent laravel?

Here's what I want to happen

$user = User::when('logged' == '3', function ($q){
        $q->where('role', 'admin');
        )}->get();

As you can see I want to get the role admin only when the column logged is equal to 3 how can I do this one ? thank you.

P.S.

just an example query. thank you.

via Chebli Mohamed