SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84fb8c30cb183308bd6ca6b275c4119dc681be36ae67a02ee77b4be9e591006c' 
  AND token = 'M8ZEchVSbZKQLIe3o4UTHs7BQEvy50STocTXEBuDWuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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