fix(api_keys): fix API key being created for non-existent merchant account (#1712)

crates/router/src/core/api_keys.rs

@@ -135,6 +135,18 @@ pub async fn create_api_key(
     merchant_id: String,
 ) -> RouterResponse<api::CreateApiKeyResponse> {
     let store = &*state.store;
+    // We are not fetching merchant account as the merchant key store is needed to search for a
+    // merchant account.
+    // Instead, we're only fetching merchant key store, as it is sufficient to identify
+    // non-existence of a merchant account.
+    store
+        .get_merchant_key_store_by_merchant_id(
+            merchant_id.as_str(),
+            &store.get_master_key().to_vec().into(),
+        )
+        .await
+        .to_not_found_response(errors::ApiErrorResponse::MerchantAccountNotFound)?;
+
     let hash_key = get_hash_key(
         api_key_config,
         #[cfg(feature = "kms")]