SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a97d5b3fd49f208c35269cafb858b1c95c2dd24115f7ea14f0eb317e701017e' 
  AND token = 'U3ekh3pLDJGA8WjhzLFDaCz0untXcza6GKeMVfFqWCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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