SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393714c5bc9dfc11e29f3130deac0ff3e1f76e847dcebd4f9fa9d9e6a16addcd' 
  AND token = 'iYqQvk/Sqcv8Grek92c6mkNjhfUFx3I/fpZgqhypxiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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