SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a65651aa6e96573a917c52abf8baf557956b052db47f2c431d2183d4b205b6a' 
  AND token = 'OYiQa4lyRI1h3QxK0SC4fupHAEMuADatInXZaFqGjUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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