SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '52fc449775ff69c0737ac63b859c98471a63f12e2cf5fa2220107b9124ca1141' 
  AND token = 'UeI+oLEDUDI0aOk0Zv8ZhkQLOvshpw1jxAk+ccF8n1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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