SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de94bf1a7c21008456a5255a221ea0a054575f821438cc00fdaa729628b91308' 
  AND token = '4Swd5jQKT9/TQMPs1dnamdeaatPhlne/70BkajxsYC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables