code: public function isApiKeyValid()
      {
          try {
              $apiKey = $this->scopeConfig->getValue(Config::XML_FASTLY_API_KEY);
              $serviceId = $this->scopeConfig->getValue(Config::XML_FASTLY_SERVICE_ID);
              $isApiKeyValid = $this->api->checkServiceDetails(true, $serviceId, $apiKey);
          } catch (\Exception $e) {
              return false;
          }
          return (bool)$isApiKeyValid;
      }
docs: Checks if API token is valid
  
  @return bool $isApiKeyValid