Is the sqlite3 cell in Python an anomaly or am I messing up?

Question

Python

Works:

spoiler

for value in sql.execute("SELECT nameboss FROM tboss WHERE death = '3:55'"):
    print(str(value[0]))
    print(timein)

Does not work:

spoiler

timein = "3:55"
for value in sql.execute(f"SELECT nameboss FROM tboss WHERE death = '{timein}'"):
    print(str(value[0]))
    print(timein)

what am I doing wrong?
as a result I want to get:

spoiler

timein = str(current_datetime.hour)+":"+str(current_datetime.minute)
for value in sql.execute(f"SELECT nameboss FROM tboss WHERE death = '{timein}'"):
    print(str(value[0]))
    print(timein)

Answer 1

timein = "3:55"
for value in sql.execute("SELECT nameboss FROM tboss WHERE death = (?)", (timein, )):
    print(str(value[0]))
    print(timein)