SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c33145cb459ffb221fea3a0906860b5dbcee91742e445af995c738eafca60742' 
  AND token = '7k7NrW1y0WjIbW0opyoURaZ4bCx6akvnfPLZuEnBCEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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