SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04b5ecccbb8b786aa75edc03c2f030eee0427431ceeac3cda5cbb11d17d3357b' 
  AND token = '5KSNeGUwnH4DUlw9L+ymqWpJi053DsCKOQPrj0Q+WdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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