A key, as opens a door or lock. Depicted at a 45° angle as a gold, bronze, or copper key with a round head and notched blade. Commonly used for figurative senses of key, e.g., the key to success, being key ("crucial").
DJ Khaled uses the emoji to indicate his Snapchat stories are official (verified). Apple’s design previously resembled a gold 🗝️ Old Key, which emoji has similar applications.
May also represent digital keys in public-key technology. This may explain why the emoji does not display in page titles on Apple’s Safari web browser, presumably to prevent less reputable sites from pretending to be secure (encrypted using HTTPS).
📅 Key was approved as part of Unicode 6.0 in 2010
and added to Emoji 1.0 in 2015.