Expired date

There is no expiration date on the back of the card. The Xbox staff @E3 also did not mention an expiration date and made it sound as though there was no expiration date, or at least any expiration date soon. Honestly, I am extremely mad @Xbox and @Microsoft
for having expiration dates in the first place. Additionally, having expiration dates when there is no mention of an expiration date on the card? There should be an internal investigation on why no dates where noted on the cards and those with expired cards
from E3, with proper verification of an expired card from E3, should be given another code to use.

You can check under your subscriptions

Or on the console.

Home screen.

Go the My games & apps.

On the left hand side go down to Memberships.

Just go to the Xbox Gold Membership.

Go into that and your expire date should show there where close the where you can redeem codes or buy subscription again.

Hope this helps a bit. Not that good with explaining where to go and such. Best of luck bud.

There's a banner that should be displayed next to your gold status.

The account page as listed above will give you all the info about your account. To view subscriptions directly go here https://account.microsoft.com/services