SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ded99132944fe4803cb882866663853c570c15f496c9f92124bdf88bd1ca195e' 
  AND token = 'Qv1WaYUeQNaqQyew1lnGoYV2pEdMaPpzYCwpDpXkbiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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