SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc87917d1c75bffec25ceb7036f181013681a5888231d2b369ee96f173476c67' 
  AND token = 'q48UH0M49gUhmB5swJqEwETWBEJuQ6BIn7ylPnVJ6EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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