The yeast is probably fine. If you have some DME you should make up a starter to get the yeast going and get some growth. But if you're working with just a kit you may not have extra extract lying around. In that case I'd probably just use it as is and it should be fine, especially if it's been manufactured relatively recently.
As a general practice it's a good idea to pick up some DME to have around and make starters with every batch when using liquid yeast.