The Tocharian B word ṣek
Word ṣek
ʂ e k
IPA ʂek
Meaning always

Comments
Douglas Q. Adams, “Etymological Dictionary of Tocharian B”, 1999, Brill

Other words that might be of interest
ente ‘when’, pikul ‘year’, ompostäṃ ‘afterwards’, postäṃ ‘after’, śāśvat ‘everlasting’, manta ‘never’, ṣe-keś ‘once only’