What response time to expect for a cached filed to be served from the service worker?

I noticed that cached files served from a service worker take way to much time according to the Chrome devTools Network tab which shows Size=(from ServiceWorker) and Time=139ms for a small image file (60×60).

The fetch handler withing my service worker is logging a cache hit for this image file so I am sure that the file was served from the cache not from the network.

Is the Time value displayed in the chrome devTools wrong or does it really take 139ms to serve a cache file? The whole point of caching files is better user experience and everything something like 2ms is way too much for a cache hit in my eyes.