SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b6fd3beea680bd5bc71ea899cf33e4c918b42e43411f83f2ee348a25a7e92211' 
  AND token = '/Z9dkJgiQ2p7DW33ez64tRpj+TwI2GZyozKJAWBdOUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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