SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3598ee987a77842c07899eacbad0eb56ea079d90f311bc3e70deb6d210a64a6a' 
  AND token = 'PsVmbKM+SWV644hMCjc3kChiVc1CaVwwXpkm3mMpoJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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