SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6095af3d10be8438ae582d530b02cb7bf0f55f41eafe2fdf08baeecc288d2732' 
  AND token = '5SNqrPPbWr8qs+KjCmpKivb2JhBiTxCSpJOiHBU28m4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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