I recently created a new app on Google Cloud Console and obtained a YouTube Data API v3 key. However, when I make a request like the one below, I receive a 403 error.

https://www.googleapis.com/youtube/v3/videos?part=snippet&q=workout&maxResults=5&key={MyKey}

The response I get is:

{
    "error": {
        "code": 403,
        "message": "The request cannot be completed because you have exceeded your <a href="/youtube/v3/getting-started#quota">quota</a>.",
        "errors": [
            {
                "message": "The request cannot be completed because you have exceeded your <a href="/youtube/v3/getting-started#quota">quota</a>.",
                "domain": "youtube.quota",
                "reason": "quotaExceeded"
            }
        ]
    }
}

Strangely, if I try the same query from YouTube Data API v3 Explorer, I get a successful response with a 200 status code.
https://developers.google.com/youtube/v3/docs/search/list

Additionally, when I check the quotas section in the Google Cloud Console, it shows that none of my quotas are used.

What could I be missing here? How can I resolve this issue and successfully make requests using my API key?