SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4726a05a0fc0d874fbcc43967480208e20ae8c730e47f58ad597c849342e6823' 
  AND token = '3pPOhwDDUgahnxEp2sRyZCuMFMYbSg0AJKD3hPfMJa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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