SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15fd902a7ea9167a05b513f34cc3e5dd637fd3f6c3d279fb847664b407ccaebb' 
  AND token = 'sq2nQfrT6T8+7bdFueqsLhMPXyNwPO5dfVZpzNiaPSM=' 
  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