SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '03fe73337911a6c272504ea166120e1ece5c4c0409e6a50ea7c7300836c66dac' 
  AND token = 'BopFhfln++OfiaIUMU6Hlhe8fkwipbJ4nHS3kdVnVBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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