SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86db39dad03a3f7abf1e0f851aa4b933d0ee2128e57b3fbbf6aa39f0c2023b85' 
  AND token = '4EljZRf4bXpPytV9mvOFfcivrVF7W5baiOWDErKVt1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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