SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f7def5eb704703aa67a9f12b76b56314679525f4b9e0c6db1439a916e98169f' 
  AND token = 'RxvRqjqjUyRNCAmMXSPYEF5SgAN0S8MjnIEgPyvJCCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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