SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc56e028974ce2e070ea78c48acfc6735fb8fecb43a697f306ec84e0365de44' 
  AND token = 'vrV78JmMuZ5uDwKOzBhNBj69VNsLhicTK1wVr0kixlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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