SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf84edbbc5354b12807267320da78a780695422c2ab1b3ca70d7819c92b1ac13' 
  AND token = 'k9ZYsgcpgKQaaEgM+vGg/Ceb7uGRgfM6Ml/xVt1MTGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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