Dashboard::SnippetsController#index is very slow due to SQL

Loading snippets dashboard takes >10s for me. According to performance bar, finding the snippets is the problematic part that takes most of the time.

From our daily statistics:

• 720 requests (rarely used) per 24h
• 98.9% of time spent in SQL

SQL timings per request:

• Mean: 5.11s
• p95: 23.42s
• p99: 25.66s

Many requests for this action are likely to get canceled as they go beyond statement_timeout=15s. While this is a rarely used controller, it renders the snippets feature unusable when it hits the timeout.