SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '170bfcae7e8c32d8bb80b77c61775c468cc37840f06e2f19db80a1159144fc4b' 
  AND token = 'p0s7YFUVfRrSVXRlb+0TfufZF9GzfN7TWqqEQP3KZvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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