SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3c8499f5a7896523e48c63e77dfe4476eb4db48946672634552580d243623c2' 
  AND token = 'lBXGqNPqQw8jsvva/S/kqUi/GYphO3YdTU1rGoesRl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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