SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424fa4a429cb71547f503870b9fb4786882305ab4f5fddad2f721866266eeabd' 
  AND token = '6yAItGu9NMQL2xwJhVcVlYD7Bok8UkItfm+7t8mCckg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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