This isn't an OTB functionality, but I wouldn't imagine it would be a tremendously hard customization.
If you really wanted to keep your effort minimal and keep the user experience close to the OTB Review Task, you could look into adjusting the Render Condition for "Create Review Task" button. I think the issue would be that the workflow expects a folder or a collection as a payload, so you'd probably need to figure out how to make your single asset wrapped in a temporary collection OR adjust the workflow to allow for single asset payloads.
If you're just looking for asset approval and don't need the UI elements of Review Task (and I don't think some elements would make sense for just one asset), probably easier to string together a few workflow steps in a custom workflow. A participant step + setting asset status would lkely be pretty simple.