title: Does Laravel's "soft_delete" need index on MySQL?
body: <p>If i'm using soft delete in laravel 4.2 (database is mysql), every eloquent  query has <code>WHERE deleted_at IS NULL</code>. There are no indexes on <code>deleted_at</code>.</p>
  
  <ul>
  <li>Will it be slow on big tables? (or maybe <code>IS NULL</code> is optimized without needing an index)</li>
  <li>Should I add an index on the <code>deleted_at</code> column? </li>
  </ul>
  
  <p>So, does Laravel's "soft_delete" <code>deleted_at</code> column need an index in MySQL?</p>
  
  <p><strong>Clarification:</strong> Laravel stores a timestamp in the <code>deleted_at</code> column to denote when a record has been soft deleted, as opposed to a boolean value.</p>