SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f455c159574118102f4d0d7eb71c3cae25745a35c0d7b4e0c32410a2acf6c93' 
  AND token = 'inLYRIAnpsiW3sWQpzqQQawDjCIGW1vJAd+Qs9Sbstk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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