Go to the website : http://www.headphonezone.in/
Open console
Type :  "Shopify.theme"
Output is : Object {name: "Retina", id: 8528293, theme_store_id: 601, role: "main"}
Type : "Shopify.theme.theme_store_id"
Output is : 601

<script>
//<![CDATA[
      var Shopify = Shopify || {};
      Shopify.shop = "headphone-zone.myshopify.com";
      Shopify.theme = {"name":"Retina","id":8528293,"theme_store_id":601,"role":"main"};

//]]>
</script>