SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9b5ce4bb32b04d7aaec326fc36ce0febe626316043d48bbc8464485a7e5fcf68' 
  AND token = 'fTAIMQyHswldqsrVgkVfmCHSk5IBtefzIHS59ZTpLvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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