SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3de196563f44b373baba3445d0779fee0a8ca5b45529e3d9894a2238c31838f' 
  AND token = 'JYBKfXckw7vET/xKyStqQnYVcasuph0eflTrJMOFKRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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