SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0008e00b5ef72fd7df49cf55be9618291a28c42a606877e2b58f95642eec4985' 
  AND token = 'xxAVfYKgTpz52ZAzjNeEzLEMwNfaYh486lqFgQJCITE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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