SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b86dca42758d947452988ef394d9e15b603bdc5800d9f21c41266af81d37ef0f' 
  AND token = 'etQrkhXqYHm7IwsWlQz1JKQFycqO2TjWI2Z5YvRzI98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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