Those who received a #Warlords beta key from us at PAX East can now claim them! Those who claimed them before should be flagged for access.- World of Warcraft (@Warcraft) June 27, 2014
If you immediately used your key when you got home from the convention, your account should now be properly flagged for beta access. If you have not used your key, you may log into your Battle.net account and use it to gain access to the beta. This is in addition to the beta invites that rolled out yesterday -- so if you happened to attend PAX East and pick up a key, be sure to claim it now that you can.