SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99cb998c03f5a4e8ded5088dfc76acbaeb9ec6f008eb3c0645a88aaab990ee94' 
  AND token = 'U3UOwfRexwKnvk8JApdmA9ZRTyCyNZwuMzMoAYfm2Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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