SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79f3eb88c785a95700bbd263a206c6757e9c64750b829f4435873a3a5a5f6dac' 
  AND token = '/ARtpptbr/hkG4lv5wcb/Ajz/ubyFj68SOrDBkpYQCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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