SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d649115a7508a1d7d6ffea6113ce7cc7b0fa87f15a9cba9572fe086b329c99' 
  AND token = 'WP0Mld+ntX1Y4MQSeTDT9PCqM4nPEjWtmpVbWrEkmoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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