SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac6f89150ceedba824aca059d25e95f781d4a018c28169043b5e8064baf6f3f1' 
  AND token = 'kDb2uBm4HIqeJ0OJOjIYWvsIcGpAyOBf0eow7jYsUQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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