SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb8045171f9df6d082ec6533bc4c43f88ba9f62851c37df443d6a1ec5a61781' 
  AND token = 'pt6g+7eZUruR7M8GLk+5yUR/HsWCstJRUywFA86l78E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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