SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d3acfce2dc9d520cfd5769e3ef60bcec7b509a7866a76fe97939c38f112340' 
  AND token = 'mXiO/OZ83yLkb2tiJk2te/BQ2YEdT+tbG3x8l39096o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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