SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '649bb541b51c1c00756e388237261f6ad2345a97b99a5225c176b76652763011' 
  AND token = 'khBbgZKJy2/NIG7j8/w/ait4tRnbBCONpLv/qko8/84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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