SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '769e749dc3992cd7ef211b94eeb4b6e3b1b1240d3f616297c92ecc12259ca360' 
  AND token = '3nDTvLWpUscztL/pEB/1FUIrfas1/jM80Wif1voDvp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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