SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae3cf5679e550d4d8c1b9b04547e1687e3ffc053026e7c12ed993a8640d23feb' 
  AND token = 'DJIF+fv9rMpE9zPiZgCI9FXxJI8B7I6vSnqjkBZWcVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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