SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e0377c3b46c63663d55fe3c310effd2628f93529c2cd80c0883effbb0c9a05' 
  AND token = 'IDVZcXWN6pGUTVLwJRLMzNtq+m0pBiqtDPtYThp9hZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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