SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a91d9bc3ee144baf53eb6fefd4fa94960907cd929342b7acd0a00fa6deb67da' 
  AND token = 'kFKKlRCPSec286+9tdWcdr5HGHi/YgJNgp/jTWNtAIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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