SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe903757eac9926b6d512bef8f2505e3d0165a141cc5dabc73d0ebe02610979c' 
  AND token = 'Plta10hBDgNZ/PnyZET0z5hlCIBTrQEUvO7Izydtc2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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