title: Reduce execution time on simple select query
body: <pre><code>SELECT sub_id, quo_id
  FROM cos_emails WITH (nolock)
  WHERE quo_id = 999624 AND sub_id = 771336 
  </code></pre>
  
  <p>This query executes in 50 seconds and returns only one record. There are 16747425 records in the table.</p>
  
  <p>How to reduce execution time?</p>