SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a7a4787af1d65716eaa95b787037c7e41079e9a9bd1f64f6953c1fabc54973' 
  AND token = '9NlL9S4myMBHq6W8Dzy7eySORLpMnbUFdHGszFxjJhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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