SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd03b8f911842a705e2603f83278e8abf38e3b20555272512c949d9a6379a8320' 
  AND token = 'XeRVdBykottfhhL1Vmkl/iB0B5G9RGxTRqBNha5FUFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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