SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3af0e33ece6409ac7c8bf8bfbae10ee856d0bfc2dbe84a8b24e7358acda9c37' 
  AND token = 'sG+s7dLNhmWQQe7Nc63EdF3QjUiDdebJseHltLiZbAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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