Bring the old card with you as well as the new. Most of the time they're just checking to see if it's the card that was used for the reservation. They may or may not notice that it's expired. If they do, tell them it was valid during the time you booked the reservation or you wouldn't have been charged for the ticket, & that you now have the new card (which may have the same # depending on the issuer). If you're especially worried you could even bring a copy of the credit card statement showing the charge on the statement. Most thieves wouldn't go to that extreme

Whenever I've had a card renewed/the old one expires, the # stays the same. It's just the expiration date/CVV # that changes. When I've had to cancel a card due to lost or theft or it being cloned somehow, then the old card gets canceled & the new card # is different. OMMV.

Cheers.