SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c8b4434717d39117a2ed040a4dc2db096c11a5696e8f951626a6dfcaf475737' 
  AND token = 'KKQMzilTj2kyLEhlkkXuV4iIVdJC1YBcTWFq/GUG+Aw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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