SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c83223490a467e565c946f8fe8398cffa622a17bd2926b9dcf44b38a7ab6dca' 
  AND token = '8MwQiDEm0wvBRzAhGT1h+kXLrKNrlDhur9Xggu7aJ0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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