SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b532881a2614c725f490cf9a2c7be10133cc79469748550781d9fa9d6a70bbf6' 
  AND token = 'urdM5a7gd/Ki/1nZN3EWIhlflvrqK66+UPkE7SJV1x8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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