SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70307607b5c39f3fd53e625b1e54ae06bc018835905bec201811e9c8b9647a1f' 
  AND token = 'jXUMu2RWNW3vSSONjyi1lGIc3ZTVLQknVf1H3fKgQK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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