It should still be fine to use. Smell it. If it has a sulphur/ammonia type smell to it - the product has gone rancid and throw it out.
If it smells normal and tastes normal, it's still fine to use.
By law, supplement companies have to put an expiration date 2 years after the manufacture date but realistically - the product will be good much longer then that. Whey protein should be safe to consume up to 5 years after it's manufacture date.