unlocking is very slow >25 seconds

I have 48 HD accounts and 5 imported accounts.
It takes ages to unlock my metamask.

I profiled unlocking and there is a screenshot how it looks like


each account calls publicKeyCreate which execution takes ~250 ms on my machine (very powerful machine)

Start with the MetaMask unlocking flow and trace the repeated publicKeyCreate calls described in the report. Reproduce with 48 HD accounts and 5 imported accounts, profile the unlock operation, and verify that account unlocking no longer takes over 25 seconds.

Written by the indexing model from the issue text.