How to avoid expiring/changing link for QR Codes

Neither InDesign or Express does anything but encode the URL it is given. If you give it a static URL, it will remain static forever. The QR code will never change once generated — note that there is no such thing as a "dynamic QR code" — and only if the destination URL changes will the 'linkage' break. (A common cause is if a special sale or promotion landing page is designated, and then that page is removed.)

But unless you are getting your URLs from a hosting, tracking or redirection service, the codes you generate are functionally static. If you are using a shortURL, tracking or redirection service, such as to generate marketing data, those URLs and QR codes will only work as long as that service is set up to accept and redirect the request.

The simple solution is not to use such features or services. The slightly less simple solution is to manage those in-house, using your own server-level address redirection, and not pay some third party to do it on a subscription basis that will expire. If you have to build QR codes around such ephemeral/pay-me addresses... you live with codes that will stop working at some point.

A bit of editorializing/pro advice: if anyone in a discussion such as you reference is babbling on about 'dynamic QR codes' as some essential technological fact, an unavoidable must-do or requirement... they are a marketing ween from one of the code-selling services and should be taken with a very small grain of salt. It drives me crazy that so many otherwise well-informed people in marketing and design believe that QR codes are some kind of mystical uber-tech that requires these 'midwives' to work. They're not. They are simple barcodes with embedded data, and you can embed any data you like without third-party support.

This may help in various ways: http://www.nitrosyncretic.com/DPR/dpr_qrcodes.php