Lost: a set of keys on a loop of red wool

Lost on Thursday evening somewhere between Plaza de Espana and the nearest bus stop: a few keys on a loop of red wool with a small brass bell, about the size of a thumbnail. The biggest is the only copy for a garage that I cannot get into without it. Years ago I would have asked at the nearest bar and someone would have kept them behind the counter. Maybe they still would. I will check this board again on Sunday.