I've received unsolicited texts with the ".biz/pyyQ" part but with different letters than your "fstcsh." I never opened them because I make it a point never to open unsolicited texts. After two or three they stopped coming so my guess is some sort of spam.
Received an unsolicited txt too, from Texas though ( 903 865 3202 ) with the same type of links. It's most likely a malware link that will infect your device without you knowing - DO NOT OPEN!