SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9844c08952491bd827e4871e8ec0eb1a048234899f19ee8b1fbaf48eae6fa7db' 
  AND token = 'vuQp7YPBI1dCFktGFQ8Vh12rBYsZq/wVwCLUnIK++sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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