SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '979c10e7ab2d80058c73e49a71e149998533344cc53dc39030d1e76bbf815343' 
  AND token = 'NQnNHzPsTyFgdn4l/z8VOFQla4LPwE5zPsIpgMZNHfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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