SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a957513afd6d81a76175fd411c770fc740f5de61b132a5f054864112d52e80' 
  AND token = 'wjlXUgQmySg9JxBFLfbRE/YuUNdisswZ3RoRU5wl+hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}