SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39a6421485d0eade70fd089133f96fc82f0b094ff9750d38b21d9fde5d3daff6' 
  AND token = 'RGY/xJ2i6oPODjiCLquuBareG6/hFfypKPH0wSRjRLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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