SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58dbc5a3eda310312af6c9ef23132ecdc59137ce89ae02694bf5b1c50971716e' 
  AND token = 'BksjhP/JHV62WyAnvuPrZw4FVbSDYBJgu1h82V77Awc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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