SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b9bb197c7804b8c4c66ed90a3dc386d1635290bf06f753506ee96ac8efd02264' 
  AND token = 'c+CZkhy+bV8qGhsKFz40TpO80mzDc5q+S3tcWVz70bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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