SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83e4771c92f04a436a62542fdc822094164ffbc7411bb900c521956dfc07cbf' 
  AND token = '2SomTtV5me+QzNK++aoAB37A2nQdMe0X6bzF2qpZY0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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