SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1171cddd4282ac136b81c61375af3926c6e764230bda712a076161a75813a2d' 
  AND token = '7GjRa0gVnwox4hakYIKvYWgGUC52exB12LHpX/+iY/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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