SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '809b0aa74eea4fee5ac0eba4c14979b8ffc52ba365e1c5a8adb13d6301fd1ad8' 
  AND token = '2CCbFarjRGNRNZFx6zSjIvPDWbHllQonliVNSyW+zYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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