SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c52ae042a2cc483e97140e34353a84e1c4ea8d7d319f55753a9fe481f0f3cb' 
  AND token = 'NIIy8K+aQXfwRU+HW2fEftv2OH9HTGEqIRQIQx8Kp2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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