SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac67bf610f83a45a34e5fbdda2c9c90453755c62467a21ab02754720134e6fdf' 
  AND token = 'kcpx9/d+hJITsYIo0rFPKhBRgBu82Bq+RJbmQhkr1Uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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