SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cc403160beb1b7b59631c61cea2ddb63d7cf8a661643737cbbf8be1b81d1cfb7' 
  AND token = 'VZ8u9etIOZ/jXTT2aVHQI16VQsv+MiZd3hkTEHyCD5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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