SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f8ba9677bc136c04cbc1867ef6189e7174d4c72b3430c1172350feb5fa3fd53' 
  AND token = 'eRBz/ScjR1QmFl4YJj9YSaouquXuu0XCI8LoHRgsKMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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