SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12083fc37114f2fd9e3b728d578ee6096950ecfb62e30905d41ddb78a2726a79' 
  AND token = '9EY8z6PAyc6v9F5WmqQh/LaHzXVR6k2DtBFM1IZi/so=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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