In the HTML which you have provided:
<div>My Button</div>
The text My Button is the innerHTML and have no whitespaces around it so you can easily use text() as follows:
my_element = driver.find_element_by_xpath("//div[text()='My Button']")
Note:
text()selects all text node children of the context node
In case the relevant text containing whitespaces either in the beginning:
<div> My Button</div>
or at the end:
<div>My Button </div>
or at both the ends:
<div> My Button </div>
In these cases you have two options:
You can use contains() function which determines whether the first argument string contains the second argument string and returns boolean true or false as follows:
my_element = driver.find_element_by_xpath("//div[contains(., 'My Button')]")
You can use normalize-space() function which strips leading and trailing white-space from a string, replaces sequences of whitespace characters by a single space, and returns the resulting string as follows:
driver.find_element_by_xpath("//div[normalize-space()='My Button']]")
In case the text is a variable, you can use:
foo= "foo_bar"
my_element = driver.find_element_by_xpath("//div[.='" + foo + "']")