SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db637be316b1f1b6c988ef18aaca983d92b5eee1e6b46f2074b27bc056cc3677' 
  AND token = 'aIjzgkc0IfXYLw2vkf3BqfazRpHt4n/WMGWNNvL38B0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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