SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '512c37943cd16999b6faf74adff40b5d1ab65dfa4ca41c68e7f13f9f1a27f745' 
  AND token = 'Cap65tnvdIIGTVkjqYhtmzWhpHws1IOzN2UI2Z3Y84k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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