SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8c4417d9561515c5bb708673fb66ab54de720b31554992d8d1706f02d333be9' 
  AND token = '8CJvrZNBF4QakvSn8ftASUs6t9AHOIrtxDvXwk/+XXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}