Being convicted of a felony will disqualify anyone. It's a given that there will be an extensive background check performed on any viable candidate. Therefore, this question is likely not seeking to ascertain whether you have served time for a prison sentence, but rather what life experiences you've had regarding exposure to a prison environment. The test here is how you present your answer to the question, and how you interpret the language to the question. They'll be looking for any emotional tells or biases you'll exhibit towards prisons when answering this question.

Whether you've been to prison, visited someone in prison, or worked in a prison environment, it's best you answer honestly. Try to tie it in with your motivation for wanting to pursue this position. If you haven't, best to relay that as well.

Try to focus on positive experiences, and an understanding of how these facilities work with their daily regimen, shift patterns, rules, etc. Going into the interview, exhibit familiarity with what the position you're applying for entails, the level of exposure you'll have to the different facets of a prison environment while exuding respectful confidence. The goal is to present that you are comfortable with the prison environment and with your understanding of what the job entails.