SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0e20e2ae7afe06326739c9be171d45e3041ace0ae30e5b395f1475d28d160c94' 
  AND token = 'MPb59TS8xCjidCG8nqF2hjqdrolChl2kUXC/epgZlYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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