SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef955e9bfb57effe09a670a7f19f7319586f676cf01e67bb90299b5081f692f0' 
  AND token = 'SUUgLjZeEE6E7tAsPqXOZdWqI/otn/fNYWh4E6yd5ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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