You could try to use acetone, but it could remove paint from the keys. I would try to remove the paint by scratching it with a pointy object, being carful of both the keys and your hands(there have been plenty of times I have poked myself trying to scrape up glue). Even if this works a little bit or slowly, I would go with it. Using acetone is a big gamble. I one spilled super glue on a desk and using acetone took off the wood stain. Mineral spirits and terpentin, though they would quickly take the glue off, would absolutely damage the keys.