Visited on June 14 and did a short charge with eCarUp app, no issue.
The parking appears to remain open 24/7. When the sports center is closed, there's another door on the side that remains open. But you could also walk through the entrance road.
At the entrance there's a sign saying 2 chargers and an arrow showing how to reach them. When the parking is empty, it's very easy to spot them, but when full it could be a bit more challenging.