SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15eedc4853b6e7fbb65b5573ca72bdfd21475cbad987c7f6712f6eec49e0e086' 
  AND token = 'PCQ/EEOjJV6f23xF2yCJixQ+q9gImM8e1Qn5+44BVWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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