Use the adjective "valid" when describing if something is acceptable, good, or okay within a specific period of time. You can replace "valid" with "good" or "good for" and the meaning is about the same:
This parking sticker is valid for 24 hours. (It’s good for a 24-hour period.)
This coupon for 50% off the purchase price is no longer valid. (You can’t use it. It has expired.)
Jorge was driving around town without a valid driver’s license.
The photo ID issued by the company is valid for two years. After that time, you have to get a new ID.
This is not a valid contract. You’ll have to find a new agreement for everyone to sign.