SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce399089b6e10ad8dfe69828894b56bad0f103edfbee706b49a3be9892e626a9' 
  AND token = 'mE6xnpeVaHUjIiocYzuyf3UxCboq7NttyFnTmC94HeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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