SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5796116d3553787449c2a60dee01277002ad8b6c3bf9c344ec240343af3c274' 
  AND token = 'CDYhIhx9/H+xfXKSXxrrkM7YuMyyKjRkHJdTUgFbnP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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