Micromax Canvas A1 (Android One) supports OTG cable?

Simple and quick answer to this question would be a NO.

Only stock Android version support OTG cable. Android One is not a stock Android version. So it won't support OTG cable. However you can enable OTG cable support by installing a app named USB OTG Helper. This app requires you phone to be rooted. Once you install the app you need to mount the directory /storage/usbotgdrive/drive.

This configuration will enable OTG support. For rooting instruction check XDAForum website. As you need to install specific file to your phone it is better to get instruction directly from developer.