SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2339b4dc4aaa6e3c9c83ca3f1419bf43a2850a8d71a50e790e462520c05fa845' 
  AND token = 'pmEQ03Y406gPxXOVsAykjUEgRwZBLYOhKXntAsfrx6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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