fix(store): use cache to check if public key exists

[b00f]

Description

This PR uses a cache to check if a public key exists or not. If not, it looks up the DB.
It also defines a new error for invalid config data.

[codecov]

Codecov Report

Merging #902 (157c8a4) into main (38372dd) will decrease coverage by 0.07%.
The diff coverage is 82.50%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #902      +/-   ##
==========================================
- Coverage   83.50%   83.44%   -0.07%     
==========================================
  Files         173      173              
  Lines        8774     8787      +13     
==========================================
+ Hits         7327     7332       +5     
- Misses       1097     1105       +8     
  Partials      350      350