SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '041bb990ec95ca19dd7676a9e9981ef5ba4f2808f3e82647e91aaa88f1adf906' 
  AND token = '1sE+/FgdwwRYsYeRqjc4sSbzQm+8VBGxnCumyhA+gus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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