Current Mac notebook computers and Apple wired and wireless keyboards (except Magic Keyboard) have Liquid Contact Indicators (LCI) to help determine if these products have been exposed to liquid.
Benefits under the manufacturer's warranty are in addition to rights provided by consumer law. You can learn more at Apple Products and Consumer Law Rights.
If your keyboard isn't working
You can get help identifying your keyboard and steps for resolving issues if your Apple wireless keyboard isn't working as expected.