I’ve just had a look for those terms on the website, and the most recent tweets seem to be in August and over 2 weeks ago.
From the Search API overview:
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.
So, my guess is that you’re getting no results in your API call because the index doesn’t include any within that time frame.
I’ve just tried another hashtag (#excited) which is more common using
twurl "/1.1/search/tweets.json?q=%23excited" and that pulled back a number of results, so I conclude that it is likely to be the recency of the results that affects that call you’re making.
For more detailed historical search results we offer the Gnip service.