SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab6ce408fff9188d68702e3c4a48c2648f1fa6bdad95b25d665923f35f0bac9' 
  AND token = 'T3gTqtxIzd6A/edJMz56UcvP5bZ3ShD4bxJ9Vl7VqSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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