SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '643741996778aef50c080867c60c6aaae3fabb54bd98d1bebbd512656a8af7e6' 
  AND token = 'O4zbe4r7It/kH7MNNkW8tpAa91OkQjdH1lIydfxPkLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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