To setup ssl for nopCommerce, we can do it from admin panel -> Configuration-> Stores-> Edit -> Activate SSL, see pic_1.
Warning: Carefully, your site will stop working if secure url is incorrect!
How to disable SSL setting from database?
Open database from sql server management studio, find the table "STORE", and update SslEnabled to false, see pic_2.
Note: If your nopcommerce version is former than 3.0, you can update 'UseSSL' statement to 'false' in web.config file.