SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cd622a028e2be0564c9f9e4b917b222a3629ee41d6849ddae9558d62009d1f6' 
  AND token = 'Leh4GQWwGjRlk08MDhj7npU/jFFpOwCcXHhE5b23x5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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