SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '403f20de0560de02fe464504f543eb5fbd441d0db2e22954bca09c8978ce260b' 
  AND token = 'OzSi2AzbnORobYBvVklGkWprKz2MVGaYj/iKTf5JAPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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