SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b41934d080c278cb6c2337fda9f66aaa8e5567c886462ed3326848b9e6271f' 
  AND token = 'yDNsNHiMJVHrx3CBy+gTiqGDulScj1kFW5yiuJvd4gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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