SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b42f12a340b51c37a1fe36db4b798dbdf157883386b87607274ba7d4efc2136' 
  AND token = 'qdbhQJMjaPojqReOiHZhIoo6qxJOiM/cyBPRRjgIYeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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