SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a8cbccf6564668082355a2ac414c353f750aaae70c525a8b2d9fb912359440f' 
  AND token = '5MzNhK1Hz/qArLtCpdAY3sv0U41aBBEbz3TGjP86Vls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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