SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa5ba269d76a2c3d3e5bd78b6e42e04b8942a2a34f232951fd288ac7d81b863d' 
  AND token = 'Re0imXnAxgnO9nkgakmtHgftU1Av8YNV3qR/yaDUo9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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