SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df155999dcdf540f2074b61a3b682a5ec0014ca0a7616a18618a01e155bd639' 
  AND token = 'MoHikXuKPfedS0NH0caLy/BGfbYvhkRuBcMWs7fBiN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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