SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c37fe5a6bf3ca86d0bc99c2c817273eab416fb4a845b3204b924a5fbd265eb' 
  AND token = '8IfnfZ54LWvUDlzFj2rXM3uBV/XjVjcQjPQ0siF8W/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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