WebElement iframeSwitch = driver.findElement(By.xpath("/html/body/div[1]/div/div[1]/div/div/div[2]/div/form/div/div/div/div/iframe"));
driver.switchTo().frame(iframeSwitch);
WebDriverWait wait = new WebDriverWait(driver, 30);
WebElement element = wait.until(ExpectedConditions.elementToBeClickable(By.cssSelector("div.recaptcha-checkbox-checkmark")));
element.click();