SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928cfb24a4617ee5f55551c6115e64d655459c482eaf4ce3ccac79d5a3255d50' 
  AND token = 'oSYGlBFJE0Dgg5K3IdQRT6NoXrqcXHH0CfH22Mabxqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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