As mentioned, is there a way to send global ESC key to close popup(CSS MODAL Window)? I tried following but did not work:
driver.find_element_by
You don't need to send keys to the element, you need to press them globally (to browser).
You can do it via Actions.
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
webdriver.ActionChains(driver).send_keys(Keys.ESCAPE).perform()
You can see more info in Webdriver API - 7.2 Action Chains doc