SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6ab2f0ada08eee28feb7bec7c80f84fdfe2853eac58ddc98cd06f20d7892380' 
  AND token = 'kUe9wsGwp4Wg4Ysfa3k/u/yMYkhnk58jyprCLu3k/JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

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