The Tweet returned by the second link there is several months old. The Search API provides access to recent Tweets (~7 days old) and is not a complete index. See the docs.
The Twitter Search API is part of Twitter’s v1.1 REST API. It allows queries against the indices of recent or popular Tweets and behaves similarily to, but not exactly like the Search feature available in Twitter mobile or web clients, such as Twitter.com search.
Before getting involved, it’s important to know that the Search API is focused on relevance and not completeness. This means that some Tweets and users may be missing from search results. If you want to match for completeness you should consider using a Streaming API instead.
The Search API is not complete index of all Tweets, but instead an index of recent Tweets. At the moment that index includes between 6-9 days of Tweets.