You can find users who have expired subscriptions by using the 'Subscribers' entry in the Admin menu.

This allows you to select users who have one role, but not another.

By default it is set to display users who have the role Subscribed but not the role Subscriber. However, you can use it to users who have any role but not another.

If you set the 'Not' role to <Any> then  the 'not' condition is ignored.