SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '346be0b01628c843bcdcc8ba814576ab006eeac62fe3cc0d8b561f61975cc217' 
  AND token = 'ASg5etG33lolCV5iePwcG5JuoodFLaBJlLVEvEVIrGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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