query_posts not working with post name and category

Hi,
So this is pretty simple. I’m trying to display a specific post but only if it’s in the category. I was wondering why this code here doesn’t work (Meaning it will display the post even if it’s not in the category):

query_posts( array ( 'category_name' => 'category', 'name' => 'hello-world' ) );
while (have_posts()):
    the_post();
    get_template_part( 'content', get_post_format() );
endwhile;

So I hacked it to work like this. This will only display the hello-world post when it’s in the category.

query_posts( array ( 'name' => 'hello-world' ) );
while (have_posts()):
    the_post();
    if( in_category('category') ) get_template_part( 'content', get_post_format() );
endwhile;

I’m still wondering why the first code wouldn’t work though.

Thanks!