SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b6eb97ebec3ab3c3d41b2fc8a7f811f89ea680739f228c6de5a32b2da477179' 
  AND token = 'ReGzCSNgLCf28p2YbJQ+MqbqnoUzMOlXR8/KPaH9QrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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