Hi All - I am facing the below error for trigger though i have filtered the condition using where clause. is there any best practise or suggestable way that i can finetune/tweak the query here?

Error : System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, AssetTrigger2: execution of AfterInsert caused by: System.QueryException: Non-selective query against large object type (more than 200000 rows). Consider an indexed filter or contact salesforce.com about custom indexing. Even if a field is indexed a filter might still not be selective when: 1. The filter value includes null (for instance binding with a list that contains null) 2. Data skew exists whereby the number of matching rows is very large (for instance, filtering for a particular foreign key value that occurs many times) Failing Query: SELECT id, OrderId, Package_Definition_Code__c, DISCOCouponCode__c, TotalActiveSubscriptions__c FROM orderitem WHERE (Package_Definition_Code__c = :tmpVar1 AND DISCOCouponCode__c = :tmpVar2) Current Apex position: AssetTrigger2Helper [47,1] Apex stack: Trigger.AssetTrigger2: line 22, column 1 Class.AssetTrigger2Helper.activeSubsCountB2B: line 47, column 1 Trigger.AssetTrigger2: line 22, column 1: []


Syntax:

public static void activeSubsCountB2B( List<Asset> newAssetList,Map<Id,Asset> oldAssetMap) {
       
        Set<String> assetCouponCodes = new Set<String>();
          Set<String> assetPkgDefs = new Set<String>();
        Map<Id, Asset> assetIdAssetMap = new Map<Id, Asset>();
        
        Set<Id> activeAssetIds = new Set<Id>();
        Set<Id> cancelledAssetIds = new Set<Id>();
        
         for (Asset asset : newAssetList) {
            assetCouponCodes.add(asset.Order_Product__r.DISCOCouponCode__c);
            assetPkgDefs.add(asset.Package_Definition_Code__c);    
            assetIdAssetMap.put(asset.Id, asset);
            if (asset.Status.equals('ACTIVE')) {
                activeAssetIds.add(asset.Id);
            } else if (asset.Status.equals('CANCELLED'))  {
                cancelledAssetIds.add(asset.Id);
            } 
        }
        
        Map<String, Set<Asset>> pkdCCAssetsMap = new Map<String, Set<Asset>>();
        for (Asset asset: newAssetList) {
         
            String pkgDefCCKey = asset.Order_Product__r.DISCOCouponCode__c+'-'+ asset.Package_Definition_Code__c;
            Set<Asset> pkdCCAssets =  pkdCCAssetsMap.containsKey(pkgDefCCKey) ? pkdCCAssetsMap.get(pkgDefCCKey) : new Set<Asset>();
            pkdCCAssets.add(asset);
            pkdCCAssetsMap.put(pkgDefCCKey, pkdCCAssets);
        }
        
       List<OrderItem> assetOrderItems =  [select id,OrderId, Package_Definition_Code__c, DISCOCouponCode__c, TotalActiveSubscriptions__c from orderitem where
         Package_Definition_Code__c =: assetPkgDefs and DISCOCouponCode__c =: assetCouponCodes];
        
           Map<Id, OrderItem> assetOrderItemsMap = new Map<Id, OrderItem>();
        Map<Id, OrderItem> updateableOrderItems = new Map<Id, OrderItem>();
        Map<Id, Set<Asset>> orderItemIdAssetsMap = new Map<Id, Set<Asset>>();
        Map<Id, Order> orderMap = new Map<Id, Order>();