SkuRepository::getCountByProductId

public function getCountByProductId(int $productId): int
{
	$filter = [
		'PROPERTY_' . $this->iblockInfo->getSkuPropertyId() => $productId,
	];

	return CIBlockElement::GetList(
		[],
		array_merge(
			[
				// 'ACTIVE' => 'Y',
				// 'ACTIVE_DATE' => 'Y',
			],
			$filter,
			$this->getAdditionalFilter()
		),
		[]
	);
}