SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b20f902209abc967d007110c1724dec6655532ae48a6e9ea4fc2ae19ce3a861d' 
  AND token = 'UzgwQgzeAbzhtr6lQgnWQdHVfbflo3jH2C8N5ILjgwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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