SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7baaac69135913e79a0d684083bfea2120485238c893ffaca945e9f78e3a435b' 
  AND token = 'eu/VBSchbO/iVYRmUrl2x+YZmql+bOeZKnosZ45DacA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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