SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97d50837312d8925897b3fff8348ca88b740de6bb209ab0e26fc38325984c1b2' 
  AND token = '6/aIy8XplaBx41GebxLWYlLg5ZJzcZfjSGv3Ne9IwrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}