The brackets in glob are used for character classes (e.g. [a-z] will match lowercase letters). You can put each bracket in a character class to force them being matched:
path1 = "/Users/smcho/Desktop/bracket/[[]10,20[]]"
[[] is a character class containing only the character [, and []] is a character class containing only the character ] (the closing bracket can be placed in a character class by putting it in the first position).
Additionally, since brackets aren’t escaped in string literals, your code will look for a backslash as well as a bracket.