SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '767c98889602aaeba524af363794a61e7f54ad712d947e40cd96c58992ff9daf' 
  AND token = 'K4CMFhbqE5pBVFI6OadfvS54OZtigdbuOaozDzGWqMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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