SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bd90bcc9f795d192c6fa0a96e7f10392b3669ca494a5d56425af63629dc0003' 
  AND token = '7bDzGsHRD/XpChs3YLerX8hrqwpLPepTQheHgyvugJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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