That is not an API call. That URL represents a web search. We do not support the Twitter website via these forums, and you should never use those URLs programmatically as that would be web scraping, which is a violation of the Twitter rules and Terms of Service.
Please demonstrate that this is an issue using api.twitter.com. As mentioned, I would not expect any Tweets earlier that 7 days ago to appear in the API search results, and this is working as expected.