SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90ecb5ad72cb7d9a228205d1be3332fd5337c264ecd63234ed90b1f683236e2' 
  AND token = 'MqfTfF8zhOb1OyDgOrFPkV9cr7dBf5YBnNtZPXTJk8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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