In most Seddurim, at certain points during davening (Ashrei, Shema, etc.), it says to touch and kiss the tefilin. The Shulchan Aruch (28:1) says
חייב אדם למשמש בתפילין בכל שעה שלא יסיח דעתו מהם
A person should regularly touch his tefillin so that he should not become distracted from them
Is there any source for kissing the tefilin, or is it just "well-known" as this question says? (The Shulchan Aruch above doesn't say anything about kissing them.)
(This is not a question of whether or not it is preferable to kiss them in general, because the Shulchan Aruch finishes off the Siman saying scholars kiss their tefilin when putting them on and taking them off, rather, it is a question specifically at the times mentioned in the siddur, as mentioned here)
If there is a solid proof to kissing the tefilin, nowadays, when most shuls require a mask in order to attend, is it preferable to try to kiss the tefilin, e.g. stepping away to lower your mask? Would it count to touch the tefilin and put your hand to your mask? Or does it make more sense to only touch the tefilin.