title: query by pages DynamoDB
body: <p>my app needs to query a list of objects from dynamoDB and I do so using an api written in python (boto3)
  I want the user to be able to view the items by pages and request the next/ previous one</p>
  <p>how can i implement in It I the api?
  my table is struct with 2 keys,</p>
  <pre><code>'key1': user1 //string
  'key2' : item1 //string
  
  'key1': user1
  'key2' : item2 
  
  'key1': user1
  'key2' : item3
  
  'key1': user1
  'key2' : item4
  </code></pre>
  <p>I'm currently using query to get all the items for a user but on large scale I would like to get it by pages. scan operation has a parameter called &quot;LastEvaluatedKey&quot; so I thought about using that parameter to set the ExclusiveStartKey and limit the result to the number of items per page but it still scans the entire table right?</p>