SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6d6b13f1cfb05f2bf1fd796ea289c53ba12fdda4286a8480a9c6c653ea2b5ce' 
  AND token = '4KXbSHsGOI84txPrFPm0MQ6UB0xv4onUe6W/0C6sIHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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