SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e49a8ec85c5a4159bba1713c8af29792f4b482ed582a485f979ca713e67e534b' 
  AND token = 'DQWgxsXqtK7++bfrEegOoJUZD5PxcrsfmvwRWGw+Owk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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