SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5db6a60467e8b8b0f5834384f1c6846752a33b495165492ed9361a5c458df38e' 
  AND token = 'egwDigevzSwU+KyUfoGUyD8q63v6hPuB8PQiiuS5k/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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