SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fdb6b05743157988f976c592967fc1b3c3efab83db72b677dfb0eabc7da9d2e' 
  AND token = '5Du4MauB+F6tzV2eV8fIPrmo/3xgwEUQ0JqBheGmGd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00101

JSON explain

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