SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861e966d8a2be020041909cbbdf15a9e190034c29744340ee5fb474df445b1c7' 
  AND token = 'tzyEOnd8j7mmauseV5Lrkv7t8KqbGmLGRCJRb0ExD+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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