Visited on April 6 and charged with M-CHARGE RFID without any issue.
Migrol's pictures made me think the charger was behind a building, but it's in fact more like in front of the building, along the main road. Unless there's a big vehicle parked next to the station, it's clearly visible from the main road.
Unfortunately, as seen before the parking spots are angled and it's in a one-way, so it's not practical if you need to reverse in.
There are foundations for a possible second charger.
I didn't investigate closer, but I noticed there's a vending machine behind the car wash, so there must be things to buy 24/7 even when Migrolino is closed. Probably not at a reasonable price though...