SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd395a91532afa34443b76aaffbb8df7427d3de6bc516c48ee065a25a3bbfaf8b' 
  AND token = 'RC2SnnEDMLTKNNK3ionypKcn7zz9ICSXKlZmgZItwYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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