If you don't find the owner via MOL, I believe that the police station is the best lost & found for items like this. You might also post a sign somewhere at the station if allowed (?
If lost at the train station, the train station may be the best lost and found since that is where the keys were left. I would give them to the ticket agent and explain the circumstances.
I didn't know that there was any kind of list and found there, but if so, I agree with Joan
I found a pair of keys at the Maplewood train station tonight. If you lost them, you know where you probably dropped them. PM me and I will get them back to you.