SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd0497594f61c76ff8bfb2f260f8ff50d71e7f3c75e8c0cdeac05784b429bbc' 
  AND token = 'dADS1wquGJy1LtDmSHdxCJMUIxH1WQiyNOIaVKax6L4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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