SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29558f75ead2a8d5f86daa649d39788fd63f82f08086005a6227b9aa6261fc25' 
  AND token = 'i3YwTBcLrU8LUNHuhl98F8ab5P9KKBQr3D+4OzkmNcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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