Improve perfomance of key listing

**Describe the bug**
Listing 1,000 keys in the ILM Administration UI yields an appaling user experience as it takes >4 seconds on develop-02.

**To Reproduce**
1. Go to ILM Admin UI.
2. Click on `Keys`.
3. Select to display 1,000 keys.
4. Observe that the request/response roundtrip takes more than 4 seconds.

**Expected behavior**
Under 1 second.

**Additional context**
Refer to #1270.
