SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0123805299f3c7c706d8d60042db369c00867b656b2955a7d9e5d827f145d383' 
  AND token = 'pzHMY1WavowrkLOC2mMx3cTgjN1zmXixCToqjqUhKQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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