SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2d4ea28122ebdb6d4b75ff6beedbf4e9a42dfef48c9ce5623e6cddc2182dae' 
  AND token = 'MyN/oa8D6chpUsHnZv72BhEq+tMpTykYPxGA9Pvph0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}