SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f85e35697425fb06df181bb9f62ccc40f36d157c35d1455e037a86d9628fb729' 
  AND token = 'nmC7B0VS10ID/33KHVYfj5EK7KZd3BqGw5aggYMXGDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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