SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78154e73fa6adab3671547f1ab3f0c94adcfb3c45dd7f3cbb2127f229e23ed38' 
  AND token = 'BLt9mRAXlI5mONYgV/3fHR4DwK2/6uvIlvX7SZ6yj0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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