SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3dbdc473787a6fd3d041c510c40484ec04df8ad001b1167a4ee6fbf59398397' 
  AND token = 'nPVhK3LJdB78Nj5ip4x0ylVaNRnBn4zZo6o4szqxGaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}