Adding indexes and speeding up doorlog query

app/models/door_log.rb

@@ -87,7 +87,7 @@ class DoorLog < ActiveRecord::Base
   end
 
   def self.show_status
-    door_logs = DoorLog.where(key: ["door_1_locked","door_2_locked"]).order('created_at DESC').take(2)
+    door_logs = DoorLog.order('created_at DESC').where(key: ["door_1_locked","door_2_locked"]).limit(2)
     door_1_locked = parse_locked_status(door_logs, "door_1_locked")
     door_2_locked = parse_locked_status(door_logs, "door_2_locked")
 

db/migrate/20141120194112_add_indexes_to_door_log.rb

@@ -0,0 +1,6 @@
+class AddIndexesToDoorLog < ActiveRecord::Migration
+  def change
+    add_index :door_logs, :key
+    add_index :door_logs, :created_at
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20140411024809) do
+ActiveRecord::Schema.define(:version => 20141120194112) do
 
   create_table "cards", :force => true do |t|
     t.string   "card_number"
@@ -52,6 +52,9 @@ ActiveRecord::Schema.define(:version => 20140411024809) do
     t.datetime "updated_at", :null => false
   end
 
+  add_index "door_logs", ["created_at"], :name => "index_door_logs_on_created_at"
+  add_index "door_logs", ["key"], :name => "index_door_logs_on_key"
+
   create_table "ipns", :force => true do |t|
     t.integer  "payment_id"
     t.text     "data"