SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f58a0e8d480f78ac281bf6162f0f4c4b434006ebf27129964fe8cd1c1375ce3' 
  AND token = 'nIg3zLKv3APF3q3RzN7weUAmT96mWcxY9csdZvplh+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}