SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fb207098ec61fdaa878c10a70e92f8b3d17b5db2ef42eedd9253bd1d1405ea5' 
  AND token = 'Rxj4SkmEnmIXmu5HFdAd0C46QzHBrXXlHXgZLnBWfOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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