SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb13d10863928177576fe890d5a4cfc776d48cc6fb70248d381b18c5a2bf5c9' 
  AND token = 'WTr5UMzP2bCnVym9B4CHLjdn9vmzXifjPOTOxsF9Tms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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