SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a006c73757ae70002348b21f60765b64fa3a0b295d1b48e70fd440ec35e9de20' 
  AND token = 'HhaQroRCoaq6rs09IyQShkDbsNvPXiAaCEtFUwp5f9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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