SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238aff5619a51afa3f43d26f8f84b96c49c88323a34c3521d481fb11611a149e' 
  AND token = '635eJXYt765hwix3BQDeHSUClT/JiWcpxUMXLIQmlp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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