SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '84543b9ce417ae72123877bfa48d4fa3b7ada37f03401e5ee675b10a8976b098' 
  AND token = '+/BOzhu2+WfIQyH/o9FNZN+hb4zw69jasi8sqSl2ypA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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