SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47f8837a1b9f899bcf06ebf9e6ad36058365388d5f9be44d847afb17106f7982' 
  AND token = 'A10hbWgloh1A7XsuIJr+HvgiM/D0LgBfZUDGKIgXJ8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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