SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a4d0357f54da3480477a562b74bd6e1e8c9b4f91693163a4d40d423899895b' 
  AND token = '0JvOXxXwWWgIOVG8pFfXkbFFtV9U5miY36gzwkZptLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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