title: Cassandra ReadTimeout when querying existing data
body: <p>For my test server, I have no-replication Cassandra 2.1.6 setup:</p>
  
  <pre>
  CREATE KEYSPACE v2 WITH replication =
  {'class': 'SimpleStrategy', 'replication_factor': '1'} AND durable_writes = false;
  
  CREATE TABLE v2.tiles (
      zoom int,
      idx int,
      tile blob,
      PRIMARY KEY (zoom, idx)
  )
  </pre>
  
  <p>For each zoom value, there could be tens of millions of small items.  For zoom=11, the first idx is in around 100352. When I need to iterate over all items, I allways see this time out error for specific storage cases:</p>
  
  <pre><code>cqlsh:v2&gt; select zoom,idx from tiles where zoom=11 limit 10;
  ReadTimeout: code=1200 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 0 responses." info={'received_responses': 0, 'required_responses': 1, 'consistency': 'ONE'}
  </code></pre>
  
  <p>I get the same error for "zoom=11 and idx > 1000".
  For idx value closer to the existing items, it gives the right result:</p>
  
  <pre><code>cqlsh:v2&gt; select zoom,idx from tiles where zoom=11 and idx &gt; 100000 limit 10;
   zoom | idx
  ------+--------
     11 | 100352
  ...
  </code></pre>
  
  <p>It also shows correct empty results when idx is compared with extremelly high value:</p>
  
  <pre><code>cqlsh:v2&gt; select zoom,idx from tiles where zoom=11 and idx &gt; 1000000 limit 10;                                       
   zoom | idx | tile
  ------+-----+------
  (0 rows)
  </code></pre>