SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '329270256d55127c89c535e4955a7435a7b0e8f1bc96b7fd3780f5aedf9eacaf' 
  AND token = 'MNNBrvjBQxrSdpdyxKpvbIZLnlo4Fhl9FOHqAQwuVhg=' 
  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"
    }
  }
}