Cushion foundation can last for as long as 12 hours, depending on the formula that you are using and the temperature of the place where you are in. If the cushion foundation offers full coverage, it usually lasts for a longer time.
Being in a hot place causes a bigger chance that the foundation will wear off faster. If it is raining, the foundation may also slide off.
As for a cushion foundation’s expiry date, best to check the makeup packaging. Usually it’s 12-18 months after opening, but 2-3 years shelf life if unopened.