SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c60fd9e348b103929cb6c5a94634717df47bf7ec58ca0f95ab14aabcb118855' 
  AND token = 'P/zDgvVylekzhEVH7AI9gt9BtYhlzIiBmJ6kgxx6cGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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