If you have sent an email that has links to the landing pages in the campaign and you then archive this campaign, the links will continue to work without issue. Archiving a campaign blocks that campaign from being able to send further emails; it does not affect the links within the campaign.

For more information on Archiving Campaigns, see the below article:

https://support.vutu.re/hc/en-us/articles/4417227271825-Archiving-Campaigns