SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a61e1f5909b1d0ffcb4109c240aec066f7f322aafba303bd1ea2398e6a725b4b' 
  AND token = 'jp8gk0ahPwCJahEF0lNvpp4OZd/i6kjTQjZZSe1EHvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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