SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b567cf08268fcac099376387d77645cca15b0a99bdf501f06d64bd8356581187' 
  AND token = 'm6jjDhK1WNKIt48lxP4o8++evAzaGz/6vYVywFGBIjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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