LDAP (Active Directory) filter expired users

How can we handle expired users with LDAP (Active Directory) user federation? Does the provider already consider the accountExpires attribute or is it necessary to configure this?

From what I found out so far is that I could filter for users that are not expired with a ‘User LDAP filter’ like

(&(objectCategory=person)(objectClass=user)(accountExpires>now))

so expired users are simply not found and login fails. But how could I replace ‘now’ with the current timestamp?

Also it seems that if a user has accountExpires=0 or accountExpires=9223372036854775807, they are also not expired (never expire I suppose).