SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbd73696d788ca5b53664e98f0b5534d981fa79a5f0da7efc98ae4b56be3385e' 
  AND token = 'O0JJq9MB9i6k/YCxOb7lblWBuDiRJxJ2sL7/b48pAd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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