Some cached records take a long time to resolve

### Issue Details

An example of a cached query that takes 42ms. I assume it's cached because it doesn't have an `Upstream` field.

`{"IP":"","T":"2021-09-25T22:40:42.958377923-07:00","QH":"play.googleapis.com","QT":"A","QC":"IN","CP":"","Answer":"","Result":{},"Elapsed":42544389}`

I see multiple of these in the log file, various domains, while most cached queries return in <1ms.

Is this normal? Is there some lock contention? GC? Or is it the optimistic cache that actually ends up going to an upstream but doesn't get logged correctly?

* **Version of AdGuard Home server:**
* v0.107.0-b.11