rails/rails — pull request #5979 by aderyabin (2012-04-25 10:55:03+00:00)
Title: sqlite supports explain too

Sqlite3 adapter is inherited from sqlite and it supports explain. And based on https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb#L121 we may say that sqlite adapter supports explain too.