SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935a6893b66b1da2b127c7551c8c8e945fa4665b2e551ada9abb6b1305bf0923' 
  AND token = '6YJNdg/DfBHfihVcKuoJ+f/9aoH2tRNVZioLjG6pMVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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