SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45cb56fd897aa5dc31e95a38bcf66f0529615aa7eef712114408e8aeb2f644f1' 
  AND token = 'XqoJW+cjzcBwPp9xH1oPUvkkffYZdNts4DuGZcAEgbI=' 
  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"
    }
  }
}