SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f8d47332151b67b670feb021413b33f464dee23b0091828ff21e2a61349f178' 
  AND token = 'LXySwvbyhOrdyZhlzZe5qfsHfbe8PqhcqUYnxA4JnQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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