SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a467cbd76b0fc6bbc7eee3134ee00a4ed99cf106633bba1152d55769b0d4cd' 
  AND token = 'KkX9g4PyQ6eQR2QoygzZsmHL1RXjT0EcFtubH6hMiFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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