SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe0a106843d909ea4dc921fa45bad13d4fa0d8e9930e2b27bc00b3f324a43cc' 
  AND token = 'oQ+VLoOqCxVa6ZV8+VhL8JoM+ckkT+7PBXNvhghlTmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}