SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff9ab30c0ac4392baeb2a24ad569c24e101a1ca20235236b4c2f28f09c32d74' 
  AND token = 'WjAqramARmoHFyURwumhKfQ1rTOvb+C27FxCI9fSIkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}