SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4ad10ccb4260e64cf3835625ffe98829df24b8066a8dfd91583c232cf1218ea8' 
  AND token = '9wRDhpil6N6PrkIGHyrsoRboMHWOSnadlkY0Kr8trcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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