I agree with mudbug. Give it a shot. It should work, but some of the yeast in the packet has very likely died. Worst case is it won't work well, so feed it with 115-degree (F) water, add a 1/2 tsp. of sugar and see what happens in five minutes.
If you happened to get two packages (or three) sealed together in a strip, all with the same 02 expiration date, I'd use at least two....if the proofing test doesn't bubble like the dickens.