SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5347479da206c6bf08204f42189a8d2ea4254967da3429440104bd07885f5031' 
  AND token = 'ad7CfxZFkqKKqh6CAJ0m0c4pb0IwatakogFlyYgU5oY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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