SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b01db9863d92acbbf62fdf1343988a9b46a5e28746ee5430efaa4582671ccd05' 
  AND token = 'tosvtgG6NUP/vBgcHOJ35u8n5tpaNQ9bIZhf1waoiRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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