SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bce9e2a78fd3c7e36bd6c32fb7797932863b73310002da728245d409ba78cf7' 
  AND token = '0WAWVYJw2OE78RVlaz0DUETURvwWnJv42lvqXNLcj0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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