SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '348563ba2b4b4837045acf4c8d2784de2517fd44289c401654f424a9c72efb50' 
  AND token = '8aVEI874w5Y+J0rXklq3Z/2u0wqFhxRGwP/M42EkDlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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