code: @SuppressWarnings("unchecked")
      public ApiKey getApiKey(final String key) {
          final Query query = pm.newQuery(ApiKey.class, "key == :key");
          final List<ApiKey> result = (List<ApiKey>) query.execute(key);
          return Collections.isEmpty(result) ? null : result.get(0);
      }
docs: Returns an API key.
  @param key the key to return
  @return an ApiKey
  @since 1.0.0