Every pack in the Time Portal short of the Standard and Premium packs are available only for a limited time, usually ranging between thee days and one week.
You may find yourself presented with offers from time to time that grant you a number of 10x pulls of a specific pack. If so, keep in mind that you will need to claim those pulls before the pack expires. Once that happens, if you have any remaining pulls, the Notification indicating as such will remain on the Time Portal but you will be unable to claim those pulls until the next time that pack is cycled back into the game.