SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31fd91890a6ec3464c91f57e48d6d1784657ee2991b9f6cfff11cac42586af24' 
  AND token = 'bl85Sj9MRhQ+jxiYTqH68sTEvxwzKehagUKGmboXp8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00085

JSON explain

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