SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d253dfe9ce15a6c8e335cd05745754b729e843d9812f9d9834da2835b68e065' 
  AND token = 'pU+hp9rPoFimfuqBCBrQVfqsbJsJxAZTDuHUcfhK2zM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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