Will variks give us a key each week for completing his bounties, I hope so because key farming is a bore and the drop rate is pretty low plus the wolves don't seem to invade as much since dlc release. Edit after reset- I did manage to find one key while completing the bounties on one of my characters but having used that key this morning whilst doing a level 32 PoE there is definitely no guaranteed exotic in the first opening of the box after reset like some of the replies I've received had stated and all I did receive was another primary weapon with no burn other wise known as a mote of life and 3 weapon materials. So there you have it, no guaranteed key once every week and also no guaranteed exotics at least not at level 32 anyway so even if you do spend a few hours farming for 1 you still might not get rewarded for it.