NoSQL, how to make "complex" query?

Question

If I created the following NoSQL table using DynamoDB, how might I query for the item with the largest ID value whose Unused value is true without scanning the entire table?

(I have zero experience with cloud platforms and NoSQL.)

+--------+------------+-----------+
|   ID   |   Unused   |   Token   |
+--------+------------+-----------+
|    1   |   True     |   ...     |
+--------+------------+-----------+
|    2   |   True     |   ...     |
+--------+------------+-----------+
|    3   |   True     |   ...     |
+--------+------------+-----------+
|    4   |   False    |   ...     |
+--------+------------+-----------+
|    5   |   False    |   ...     |
+--------+------------+-----------+

Answer 1

You create a Global Secondary Index with Unused as the partition key and Id as the sort key.

Unused	ID	Token
True	1	---
True	2	---
True	3	---
False	4	---
False	5	---

Using a Query you can do the following: SELECT * FROM mytable.myindex WHERE Unused='True' LIMIT 1 DESC

This blog will help you to understand the pros and cons.