SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52a968d21fc9074f76f62dd4b5c072568023fd593d63ed1522a8311a8ed3587' 
  AND token = 'V7jEkrAwg857A/PJj53yuLpGVYOv36B14i+xyxXRVCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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