SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d90f070fa63ab007fe692a5fe9466a17ec78cdc697d9ffb457c33aa079ebb3' 
  AND token = 'A9PcvGriY3lseNMjq+O6wtUj0lxMniACAWIYeUpIFog=' 
  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"
    }
  }
}