SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248ac78eadb85289655a998d44f3962b018455eb17b362755553183b42029a7b' 
  AND token = 'NGQlk+y2y9H2+It1fQsUK/OUM+dyj+Y02OjX18dYHqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

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