title: multiple indexing with slow query
body: <p>In following query I indexed every field like:</p>
  
  <ul>
  <li><code>menu.id</code></li>
  <li><code>pricelist.menu_id</code></li>
  <li><code>vendors.id</code></li>
  <li><code>pricelist.vendor</code></li>
  <li><code>orders.pricelist_id</code></li>
  <li><code>pricelist.id</code></li>
  <li><code>users.id</code></li>
  <li><code>orders.user_id</code></li>
  <li><code>orders.free</code></li>
  <li><code>pricelist.menu_id</code>.</li>
  </ul>
  
  <p>When I run the below query it takes much time, we have 13 million records in <code>orders</code> table and other table has few thousands. </p>
  
  <pre><code>SELECT
      `orders`.`itusername`,
      `orders`.`iturl`,
      `orders`.`error_message`,
      `orders`.`return` AS return1,
      `orders`.`coupon`,
      DATEDIFF( users.reseller_expiry, now( ) ) AS edays,
      `users`.`email`,
      `menu`.`menuname`,
      `orders`.`error_status`,
      `orders`.`auto_status`,
      `vendors`.`name`,
      `vendors`.`id` AS venderid,
      `pricelist`.`servicename`,
      `orders`.`email_order` AS paypal_order_email,
      `orders`.`user_id`,
      `orders`.`services_order`,
      `orders`.`created_dt`,
      `orders`.`id`,
      `orders`.`transaction_comment`,
      `orders`.`url`,
      `orders`.`requireviews`,
      `orders`.`youtubeviews`,
      `orders`.`total_views_completed`,
      `orders`.`aff`,
      `orders`.`is_package`,
      `orders`.`price`,
      `orders`.`order_from_site`,
      `orders`.`cost_per_unit_order`,
      `orders`.`service_name_order`,
      `orders`.`status`,
      `orders`.`start_api_date`,
      `orders`.`end_api_date`,
      `orders`.`allow_setting`,
      `orders`.`return2`,
      `users`.`balance` AS user_balance 
  FROM
      ( `pricelist` )
      JOIN `menu` ON `menu`.`id` = `pricelist`.`menu_id`
      JOIN `vendors` ON `vendors`.`id` = `pricelist`.`vendor`
      JOIN `orders` ON `orders`.`pricelist_id` = `pricelist`.`id`
      JOIN `users` ON `users`.`id` = `orders`.`user_id` 
  WHERE
      `orders`.`free` != 1 
      AND pricelist.menu_id = 3 
  ORDER BY
      `orders`.`id` DESC 
      LIMIT 10.
  </code></pre>
  
  <p>.................................</p>