SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713fb5bf80ef7bf33308b297776dd8009ddf9172c491c76b6ef4fd4f9740fec7' 
  AND token = 'x8aBBHdqM2nFRWl532wVi+tQKm6CgSTgI7ZKtSaWWC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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