SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a87e72ce652a0925abc1f313f8d8521cb74c898272eef56a438ba8f672f739d' 
  AND token = '3MYP3Xvj+BrhPYJLaeacOo8jSegdU6eYA7uZZdxyFHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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