SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc48d5217651990223aa29bf11514b996926fa920b618976f103de21d7fce036' 
  AND token = 'YH2BFmjzNvOylPlZn3Kxywj+TO3/vE8eSv3OZYUHa9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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