SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '157bc21412bf41bb8c31a78bf40cc6c21455010393a98258bc1b9a0b08879fa6' 
  AND token = '9QuontDB7BIf9A9h13Eljm092UO/Jkfi0h4J2w5mMMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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