Please find the below Business Rule:

Table: sc_cart_item

When: before, insert

var gr1 = new GlideRecord('sys_attachment');
gr1.orderByDesc('sys_created_on');
gr1.setLimit(1);
//gr1.addQuery('table_sys_id', gr1.sys_id);
gr1.addQuery('table_name','sc_cart_item');
gr1.addQuery('file_name', 'CONTAINS', '.xlsx');
gr1.addEncodedQuery('sys_created_onRELATIVEGT@minute@ago@1');
gr1.query();

if(gr1.next())
{
//gs.addInfoMessage('Excel: inside while: attachment: ' + gr1.file_name);
var header_count = 0;


var parser = new sn_impex.GlideExcelParser();
var attachment = new GlideSysAttachment();
// use attachment sys id of an excel file attachment
var attachmentStream = attachment.getContentStream(gr1.sys_id);
parser.parse(attachmentStream);
//retrieve the column headers
var headers = parser.getColumnHeaders();

var a = headers[0];
var b = headers[1];
var c = headers[2];
var d = headers[3];
var e = headers[4];
var f = headers[5];
var g = headers[6];
var h = headers[7];
var i = headers [8];
var j = headers[9];
var k = headers[10];
var l = headers[11];
var m = headers[12];
//gs.addInfoMessage('Column in the attachment contains: ' + a + ', ' + b + ', ' + c + ', ' + d + ', ' + e + ', ' + f + ', ' + g + ', ' + h + ', ' + i + ', ' + j + ', ' + k + ', ' + l) ;
//var obj = {};
// while(parser.next()) {
// var row = parser.getRow();
// //print row value for both columns
// gs.addInfoMessage(row[key] + ': ' + row[value]) ;
// obj[row[key]] = row[value];

if(a!='Asset tag' || b!='Serial number' || c!='Model category' || d!='Model' || e!='Owned by' || f!='Managed by group' || g!='Managed by' || h!='Assigned to' || i!='Company' || j!='State' || k!='Substate' || l!='Location' || m!='Cost')
{
gs.addErrorMessage('The columns used does not match with the template. Kindly review the template');
current.setAbortAction(true);
}
}