Picking a bike lock

Suppose you left your bike outside a coffee shop while you were working, and someone accidentally put a lock on it. The lock consists of 3 separate tumblers, and for simplicity, each tumbler only has 3 distinct letters in it. The lock can be represented in the following array:

the_lock = ['ABC', 'FDG', 'WYQ']

You're thinking about trying to crack the lock (rather than calling for help or walking home) -- given this information write a function to return all possible combinations that can be made by the lock.