SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d728d59286c0c453c5aa9f07e3153a530c289babe75629a3ae2c597c8ae5f94' 
  AND token = 'fnd9pKncCJgPLyDXwrXpjpDp98YlI0XWzhDEx6gsWrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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