SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '391a54c512ea4bf0da1ecd9e73c722a59b986c29d020a470aefc64f6c340f43a' 
  AND token = 'jPa41tc4umM+F+mWKC1wESuak/mMBnWAQq6TSL0T9YY=' 
  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