SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dd6c586d129c3e576be693117d5b6f108ec4269cc51dcda6139422374671d41' 
  AND token = '7l5fJG3VVJXq8Jzvn9ZMbn28xiakMah1Q6QbHyLKIM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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