SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0826a031c7fdc2ec8419fdb24f1cd6a1e0887273f719fe9d4120ddaefc275d' 
  AND token = 'U8dx3i6pJfERnU/Gh6CPIIGmwX1RrDzVZpKqhDD3tJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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