SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d35aec524ca862a4a2e78933ea8840cf11a8493f1082f2f51095be2fc53f6a8' 
  AND token = 'CwdadWBprr9ZwFvpXe2BL56ovA5k29tCCdHWuoKLgis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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