SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa2839c9d5fbc8ceed2cf7bb359c54e5ddd2fd00d94156bce32b426218acac0' 
  AND token = '1Y/4cIZ98AjqRReMzOPs8ngCEIa2DGTfGn4ACgQaiJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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