SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2aea80763dd98e1c343313b51d8d76d3ba7a3e9d7bd60c925cfb79189e50072' 
  AND token = '6EmDbBfWGGI+joYl7sENWD0UShOYEGQrD3LvGpD034I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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