Get it printed on a physical monument made of metal/stone, put it on property you own, and engage a lawyer to set up the will and property covenants to require its ongoing existence and maintenance.
Our guesses about what the web looks like ten years in advance are likely to be wrong, let alone 500.
You'd have to also include plain English instructions on how to read the QR code, since the QR code format probably won't be around in the future either.
As for reading the instructions: they could probably still interpret modern English, similar to how professionals today can still interpret English from 500 years ago (with some effort).
Our guesses about what the web looks like ten years in advance are likely to be wrong, let alone 500.