Blizzard has made a blue post about the change of Keywardens as below, also diablo 3 items are available on our site. Check here if you need:

Areas in which Keywardens are located now have a boss icon on the Waypoint map

 .The icon will indicate whether or not the Keywarden has been killed

 .This is only for level 60+ games

Nekarat the KeywardenHas been moved from Silver Spire Level 1 to Gardens of Hope 2nd Tier

As the blue post showed, Keywardens are noe global drops. The common way to farm for keys was for 2+ players to head to the same area and spread out, rushing through the Fields of Misery, Dahlgur Oasis, Stonefort, or Silver Spire Level 1 Gardens of Hope 2nd Tier. Whoever found the keywarden would alert the others and wait, not killing the KW until everyone was in the vicinity so they would be eligible for the drop. Also there is a new way can be used. Each Keywarden will drop a key for everyone in the game, or no one — it’s all or nothing, so everyone gets a key, or no one does, from each Keywarden, and the best odds are still just 50% on T6.

Blood Thief Exploit we talked before did not change how Keywardens drop. We will keep updating new information about this. By the way, feel free to buy diablo 3 items on our website.