SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3bc13f29c346f14a0550f3152c923f4af7d4e466e2702d76698194903aced226' 
  AND token = '6oXqafHHUgAsSe17/sQPH5IESPiBSizjhBjR46wvpSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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