SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fddda59a13f1995c76981829d88b21fce916c005a4f6181239bfdc4067387fa' 
  AND token = '9YFgmk3JcAaPg3/WZaSfz162G5TyhBIkonAZxJFIzG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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