#vendor/magento/module-vault/Model/PaymentTokenManagement.php::getListByCustomerId()

   /**
     * Lists payment tokens that match specified search criteria.
     *
     * @param int $customerId Customer ID.
     * @return \Magento\Vault\Api\Data\PaymentTokenSearchResultsInterface[] Payment tokens search result interface.
     */
    public function getListByCustomerId($customerId)
    {
        $filters[] = $this->filterBuilder
            ->setField(PaymentTokenInterface::CUSTOMER_ID)
            ->setValue($customerId)
            ->create();
        $entities = $this->paymentTokenRepository->getList(
            $this->searchCriteriaBuilder
                ->addFilters($filters)
                ->create()
        )->getItems();

        return $entities;
    }