Regular keyboard or laptop keyboard??
If laptop there are ways to clean them - but I'd suggest doing a search for that info and your laptop brand name.

Regular keyboard..
Sometime crud falls down between the keys..
turn it upside down and tap on the back, shake it side to side and see what comes out.

If a sticky liquid might have gotten in there then a more though cleaning is needed.

many of the newer keyboards can be rinsed out but have to get dry before using again.
I keep a spare keyboard for those times...and just in case it doesn't help at all.