I would replace the keyboard. They are relatively inexpensive, while a bit tricky to replace, but doable with the ifixit guide. It is clear that the keyboard takes the brunt of any liquid spill, and that any shorts will occur there. I replaced a logic board on dead Mac once, but it still was dead: only to find out that all I had needed was a keyboard with the integrated on/off switch. The way to test if it is the logic board, or if it is the keyboard, is to find the on/off tabs on the logic board and bridge across them. Mine booted right up and proved that only the on/off switch (integrated in the keyboard ) needed replacement.