There are a few different ways that key beds work. Some use brass springs, some use rubber mats, like in a computer keyboard. I'm sure there are others too, but those are the two I've seen. If you are lucky, the liquid has covered the contacts and is stopping them from properly meeting, so pulling it apart and cleaning it may work. Dunno about the touch strips, that actually makes me worried it might be a chip that has been fried.
I've found that the box is pretty sturdy, after I unpacked it and put it on my chair then lost balance and sat on it as I fell. The keys all worked as they should despite the crunch it took.
Years ago I bought a Frostwave Fat Controller (analogue step sequencer) and spilt Coca-Cola over it. After opening it and cleaning up the mess, the letting it sit for a couple of days to ensure it was dry, I fired it up and it was fine and is still running today. After may spill accidents with electronic devices in the past, I've learnt it's always best practice to let the device sit for a few days for all moisture to dry before powering up for a test.
Good luck, although the Keystep is an incredibly low priced machine, it would be terrible to have to fork out again to bring back the joy it contains.