Get a single blocked key

curl "https://api.phrase.com/v2/projects/:project_id/blacklisted_keys/:id" \
  -u USERNAME_OR_ACCESS_TOKEN

{
  "id": "abcd1234cdef1234abcd1234cdef1234",
  "name": "date.formats.*",
  "created_at": "2015-01-28T09:52:53Z",
  "updated_at": "2015-01-28T09:52:53Z"
}