SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56da3d6e45220bc7c08b7f2502da264e4647d96b6bcc70a75f6789f15946090d' 
  AND token = 'xjXWvWkLLfGqkQQ/W4VBy+fE+JP1g/RIqZo9j7BnRGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}