SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1be7bdccc801b9735cbf822a1024aff43c604590f5c9b11c2fdb477e779d5a4c' 
  AND token = 'BTuBAdyWCl8PwI+YtIuD5QyAIXZQIInQRypN237KibI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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