SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248793867e697ce32110446c17942167fbc37a4e7ffbaeefd7bfe3a6e5969648' 
  AND token = 'ZeqSHh+imZcvshWNwy6oE0PUxsuRg8lJCnGDnJYl6JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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