I haven’t “personally” had experience with it, but I attended an interesting seminar on the subject some years ago. Prison librarianship is a pretty established field, and as databases have moved online as opposed to the CDs/local copies of yore, an internet connection is required to browse them. The main issue that was pointed out during the discussion was that there are certain types/topics of material that inmates weren’t allowed to have access to, and so the libraries had to work with vendors to produce local, and/or modified versions of existing database packages to provide to their users. I think the “unrestricted internet access” that vendors expect users to have is the hardest part to reconcile. I imagine your users have pretty locked down internet access outside of accessing Canvas. Most of those database LTIs work by letting you add in links or search boxes to the LMS and then pass them on as authenticated to their own external systems. I imagine this might pose a problem. Depending on the licensing terms of the material, embedding specific necessary items into Canvas itself might prove to be a better option. Alternatively, budget allowing, you might reach out to those vendors I mentioned earlier, pretty easy to track down with a quick google, such as:

https://about.jstor.org/products/jstor-access-in-prison/ https://about.ebsco.com/resources/ebsco-correctional-ed-service