Confusion caching Active Record queries with Rails.cache.fetch

My version is:

• Rails: 3.2.6
• dalli: 2.1.0

My env is:

• config.action_controller.perform_caching = true
• config.cache_store = :dalli_store, 'localhost:11211', {:namespace => 'MyNameSpace'}

When I write:

 Rails.cache.fetch(key) do
     User.where('status = 1').limit(1000)
 end

The user model can't be cached. If I use

 Rails.cache.fetch(key) do
     User.all
 end

it can be cached. How to cache query result?