SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f2a3e6a6dd7f779ab68cf885c4fe98d3bd312fba14407151f03262c03d42370' 
  AND token = 'xNT7YHrYmkSijSHf4mMXiRKq/UY0zPsh9f+cQcYF/4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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