[He knew that it was recklessly but his curiosity was bigger. He stepped forward to take another look at the glass case. At the first sign he couldn't find a spot that was resembling a hole for a key. Even there would be one, how likely was it, that the key was somewhere near the case?]

It doesn't seem to have a place to put a key in. I am sure there is either a technical way to open it. I doubt that you have to whisper some magical words to it and it opens up on its own.