SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4681549a3ff58a6e5dea071e506910159515996b770f5122dcf37bc9c873d9b4' 
  AND token = 'skECj4rLKVLmt3veP9uU8B6txF6UoDD+qhWQWXwMYps=' 
  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