SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d8b692dbd5d192f9ee6cc1d88659c36b2cf273ee96ba5f2735f759a1d99426c' 
  AND token = 'vQZD4cFsMH175x1tdbogq6uTuYtPFCAOvJ/JXY7LTz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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