That is reasonably fast. We wrote entire games in PHP where we aimed for wall time under 100ms. That is a challenge, but often doable. Some routes managed to respond in under 50ms.
You probably haven't heard of them. We were a German studio, and most of our games only reached a few tens of thousands of players. The biggest hit was Xhodon — it had a bit of a following among World of Warcraft fans. It was a fun time.
I spent a colossal amount of my childhood and teens playing browser-based games and have zero regrets!