Apple

try using a small amount of goo gone. It's just citrus oils pretty much and is fairly effective in removing adhesives, I used it on uniforms in the past to remove patches, it doesn't discolor or corrode anything.

Loctite recommend for removing superglue from (specifically) plastic:

"Getting glue off plastic is straightforward. Soak a cloth in vegetable oil or skin moisturiser and rub it against the glue. Wait for the substance to soak in, and then clean the surface. White vinegar also works well: soak the area in vinegar, then remove the glue with a dull edge such as a spatula."

If I was in your situation, I'd mainly be concerned about gunking up your keyboard by getting further stuff underneath/around the keys, or worse, liquid making its way to the electronics underneath.

So, while I can't recommend it because I haven't tried it, what I'd do is bung tissue paper between the gaps around the key, ready to soak up any excess liquid. Then carefully put a drop of vinegar onto the superglue, let it sit for a minute, and try scraping the glue off with a fingernail. I don't have a pipette, but I'd be worried about trying to extract one drop carefully from an entire bottle, so I'd pour some into a bowl first, then dip something into it to transfer a drop.

If it is only on the keycap (and has not gone into the keyboard mechanism), my recommendation would be to let it dry. You can always get a replacement keycap off amazon or ebay. A trip to the Apple store may even get you one for free - if they happen to have a dead macbook hanging around out the back.