SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '994edb77b2799517fb71c629b7c4eac8a1402f5217bb63eb3b75362531e815d8' 
  AND token = 'xXajzn3XHowU891VNXycJWlFqybe7NFzm9YJVaoCFFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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