SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bfd98f8ed4ee1b3ba795fda8662e68092c6b08a531755b1cccd9f1d35945df2' 
  AND token = 'oxYnSfpzrDK4VkAqv7WxexmbdkvIK5CbHxbnIYxUJ6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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