SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec42f575a396dd430e94dcb18ecf1e9ebaab5fa62860811f920cec1dc9ce3536' 
  AND token = 'NVilkqpVb6Tbj70LERDoFLeLsai+C0q6Ovhg61RAWOs=' 
  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