SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1b9ff797ff0e706b37170d666fa05f5ced4d467275ff5a73cc9fa8521127cd' 
  AND token = '9vlyrDdpPNJdlHHeDZY0ZrE3MP1q67sWh77qsWJy5BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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