SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'be9b490514b8392ee71de66cd28ccc0e59b42367e3677b18f8d9301805662afe' 
  AND token = 'SWrxO/624HIcB1ib908BHs19eocDKMssSPrSJyUEBv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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