SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a43d77309c68467e978a978da096115f5cc1210734d515dc5c37626c19206f4' 
  AND token = 'zK1ZmPkiy0cSXjUsErjEZy0ySwvoBrXLglkNAqdy/UI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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