SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd16e966e323385022af226eff96bf992fcbb31a9b96eab8193279177d1f49d2d' 
  AND token = 'lRffnRqkWd/crwa+ZvtmHKBy7+5gPr8iFU62HzmcKns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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