SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c75c18a73a624fb7ea67c41ea91245e08e9329c7848ea72c0666dbc668968d' 
  AND token = 'yfNAuXzXd/LkYyR3iebW0fNJxFcjAFXMHJFKIVnIB0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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