SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b55461d74edeb5a34bfbba47eb9ed6c455c351c3ef5c9cba8967e45abc45da5' 
  AND token = '9M45uXjmrpEEcUzV8ez4cueJ/IcvjYLcv3YGuR/qT6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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