SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8512b0f313bf903a609f32ba417a0f88e01de6e6afb91db272d7823b8355a8ca' 
  AND token = 'iE0G/eLxY4wXVtocfmzOIPitdTkjg0gLgHqzjHmEwbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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