RPGMemes

If the lich is dumb enough to use a mundane lock, there's easier ways to get through it. I guess they could do that trick with Imprisonment (Minimus Containment) to get an indestructible gem, but you could still use Stone Shape.

The proper way to hide a phylactery is in a demiplane with a bunch of random knick knacks so people can never guess the "contents and purpose".