SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b94855c5b10e12f1af296d305acc1a3eecfb3366564b65ff8d5057ea7928e49b' 
  AND token = 'sZ6YLLKCScYY8BBi7bO8YdDUSoshlKMUWXJBmnCCw8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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