Prevent access a file in public folder

I have a json file inside a public folder. I want to restrict the access to the json file from browser but it can be accessed from controller. I do not know how to do it.
For example, json file is placed inside key/foo folder which inside public folder → public/key/foo/bar.json.
I created .htaccess (Deny from all) file in key folder but I still can access bar.json from the browser with this url path http://localhost/key/foo/bar.json

Any help?

Thank you.